Diffractive optically variable image devices (hereinafter DOVIDs) are diffractive images based on optical interference techniques. One class of DOVID is a hologram where multiple perspective dimensionality is preserved. In layman's nomenclature, the word “hologram” is commonly substituted as a generic term for DOVIDs. Another form of DOVID is grating imagery where only a single perspective dimensionality is preserved.
DOVIDs have been in used in many applications to protect replication sensitive documents. Some of the first uses of DOVIDs involved the protection of credit cards. Since then, several types of diffractive imaging technology have been developed to increase the difficulty of producing counterfeit documents.
All DOVIDs present a reflected image which changes appearance when tilted slightly at various angles. This unique characteristic makes a DOVID image impossible to copy or imitate by conventional printing and computer based graphical hardware and software processes.
Current DOVID technology used to protect replication sensitive documents, for example identification documents such as credit cards, relies on generic DOVIDs that have no ties to the actual information that is present on the documents. Further, DOVID material that is currently in use is becoming increasingly available on the gray market in which the DOVID material is initially legally obtained but later sold or distributed illegally or under questionable circumstances. As a result, conventional generic DOVIDs are becoming far from secure.
What is needed is an enhanced security document, for example an identification document such as a passport, driver's license, credit card, identification card, and the like, that more effectively utilizes DOVID technology, as well as improved methods relating to the production of such documents.